Incurably curious. I write about science and the mind from a critical perspective. Blog: neurobonkers.com

Apr 20, 2016

Sativa vs. Indica: Fact or Fiction?

The labels at your local dispensary are likely flawed

By Simon Oxenham

According to cannabis folklore, there are two separate strains of cannabis with wildly different effects. Dispensaries and stoners alike will tell you that “sativas” give a heady, cerebral, stimulating rush, while “indicas” have more sedative properties, leaving users with more of a “body high” that sometimes puts them in a state of “couch-lock.”

Scientists believe sativa strains with their tall stems and long thin leaves evolved in hot humid jungle climates. Meanwhile the shorter, denser, indica varieties with their wider leaves evolved in more desert-like conditions — though where exactly is still a source of controversy. This is due in no small part to the fact that both strains readily interbreed with each other and grow in diverse climates, with or without the assistance of humans.

After examining decades of evidence, cannabis researcher Dr. Ethan Russo recently stated in an interview published in the journal Cannabis and Cannabinoid Research that he believes the sativa vs. indica distinction as commonly applied is entirely meaningless. Which would mean that the effects of your Green Crack or God’s Gift can’t be predicted simply by looking at the plant.

THC (tetrahydrocannabinol) is often discussed in articles and blogs as the “active ingredient” in cannabis, but when THC has been isolated and given to patients on its own, the result is often extremely unpleasant. It is widely believed that this is because of the absence of another important cannabinoid called CBD (cannabidiol) that may counter the anxiety-provoking effects of THC. In fact, CBD has been proposed as an antipsychotic, antidepressant, and even a stimulant in low doses.

Left: THC, one of many active components in cannabis. Right: CBD, possible antipsychotic, antidepressant and stimulant.

CBD, as well as many other important beneficial phytocannabinoids, has been all but bred out of black-market cannabis in the U.S., the U.K., and continental Europe, Russo said. High THC preparations known as “skunk” overwhelm a black market that has a vested interest in packing a powerful punch and no inherent concern for customers’ mental health, long-term wellbeing, or medicinal benefits.

“When people sell things as sativas and indicas and hybrids, that designation doesn’t necessarily mean anything about the chemical composition of the plant,” said Ryan Vandrey, a behavioral pharmacologist at Johns Hopkins. “To put things in perspective, you can look at a dispensary menu — and they have 75 types of cannabis on there — and when you scroll through, some of the more sophisticated folks will have the THC and CBD profiles for their 75 different strains, and there is a really, really narrow window of variability. So in these 75 different strains you have essentially the same THC and CBD content. Then why is it that the budtender in the dispensaries is able to tell you that the Purple Purple or the Big Bubba Kush, or whatever you want to call it, is better for pain? While this other one is better for insomnia?”

In addition to THC and CBD, there are more than 100 cannabinoids — many of which have been found to have potential medical benefits. While these cannabinoids play some role in the effects of different strains, according to Russo, chemicals other than cannabinoids are responsible for you sitting on your ass watching television when you’ve had one too many hits (aka “couch lock”). Russo argues that the couch-lock effect may be the result of the terpenoid “myrcene,” a recognized sedative and painkiller also found in hops and used in sleep aids.

However, Vandrey expressed some doubt about Russo’s myrcene hypothesis. “There is really, really limited science on that,” he said.

Myrcene may be the leading cause of “couchlock”

Reports from Test Lab Amsterdam, a cannabis testing laboratory in the Netherlands, complicate matters further. They largely agree with Russo that myrcene plays a role in the high, but hypothesize it may be the cannabinoid CBG in combination with THC and myrcene that creates couch lock.

Test Lab Amsterdam Lab Manager Pars Manas Akdag agrees that you shouldn’t pay attention just to strains, but feels the classifications aren’t completely bogus, either. “All of the indica strains contain higher amounts of CBG in comparison to the sativa strains,” Akdag told me, saying that this may explain “the sedation/deactivation and couch-lock effect of the indica strains.”

So, is there something to the folklore that indicas and sativas are different? Without hard evidence to back up these claims, we just don’t know. But if there is some key biochemical difference between the strains, it probably isn’t the one we’ve been led to believe. What we do know, however, is that we are all highly vulnerable to suggestion. The placebo effect doesn’t just have the power to affect the body, it also affects the mind. That’s right, the placebo effect can get you high. Therefore, it’s very possible that when you read that a particular strain is a sativa and you expect a certain type of high, this becomes a self-fulfilling prophecy.

With so little scientific research into the different chemicals in cannabis, it’s safe to say that no one knows what effect a strain will have just by looking at it — and certainly not the budtender at your local dispensary.

Practically nothing is known by way of controlled experiments about the effects that chemicals like myrcene can produce when inhaled into the human body. With so little scientific research into the different chemicals in cannabis, it’s safe to say that no one knows what effect a strain will have just by looking at it — and certainly not the budtender at your local dispensary. But all of the cannabis researchers I spoke to agreed that the name of a strain and its THC content don’t tell enough for you to anticipate how high and what kind of high you will get from smoking it. The only way to get an idea (without consuming it yourself) is to test a sample of a strain by examining its chemical components.

Don Land, a professor of chemistry at the University of California, Davis told CBS San Francisco reporter Mike Sugerman: “Because of the federal status of cannabis right now, those federal agencies that do all of that monitoring are not allowed to do it.”

The FDA simply isn’t allowed to touch cannabis, even in legal states.

In 2014, Sugerman, himself a medical user, ran bioassays on $600 worth of cannabis from 12 random dispensaries in San Francisco and Oakland. His findings were far from encouraging. Even where basic potency was listed on a label, the amounts were off by as much as 98.7 percent. In most cases, Sugerman found the reported levels to be up to 50 percent off from the actual levels when independently analyzed. Professor Land reported cases where he found “someone is in the back making numbers up and putting them up in front, and we showed them they were very wrong.” Sugerman himself suffered from poor labeling, lamenting, “Sometimes I would get really high. Too high. Sometimes, taking the same amount, I wouldn’t feel a thing.”

This lack of knowledge about potency and effects may begin to change with legalization of cannabis. The cost of equipment necessary for basic tests begins below the $1,000 range. Therefore, it is not completely unrealistic that such tests could allow accurate labeling to become the norm, and that researchers could move our knowledge of the substances in cannabis beyond the current realms of speculation.

It is astonishing that patients around the world must make what is ultimately an important medical decision based on little more than educated guesswork. And it is rare, indeed, for scientists to put their credibility on the line and speculate about a drug used by millions of people. However, at this point they have no choice — the evidence just isn’t there.

Time is a key barrier to implementation of bioassays by dispensaries that is often overlooked.

“Personally, I love Dr. Russo’s point of view,” said Chris Schutz, director of business development for Sequoia Analytical Labs in Sacramento, California. “If we had the potency values, terpenoid profiles, and a bioassay, we could get away from the confusing strain names and really understand how each different combination of genetics is going to affect you. The problem is that biological assay analysis takes a long time.”

The analyses can take up to six weeks in some cases, while basic potency measures and all other testing is turned around in as fast as a day.

For now, comprehensive tests are the only scientifically proven way to determine if that pot brownie is going to knock you out. Hopefully, they’ll start becoming more common with the increase in legalization. In the meantime, stop relying solely on the sativa vs. indica distinction. Unless your ganja has been under the microscope, you really don’t know what you’re getting.

Simon Oxenham is a science journalist based in the U.K. He is known for exposing and debunking misinformation and keeping a watchful eye on controversial findings within the fields of psychology and neuroscience.Simon has written and blogged for The Psychologist, Nature, Scientific American, The Guardian, and Big Think, among others, and has a weekly column at New Scientist. Follow him on Twitter, Facebook, or join his mailing list.